Global position system (GPS) integrates satellite and wireless technique to provide users with accurate position, speed, and time information. Presently, GPS has been widely applied to mobile devices in the market, such as mobile phones, personal digital assistants (PDAs), car PCs, etc. Besides conventional positioning functions, the mobile device equipped with GPS can also provide advanced functions such as trip planning, voice navigation, scenic spot searching by incorporating with an electronic map and navigation software, so as to facilitate users resolving trip problems.
The conventional GPS device has a built-in electronic map, and provides functions of trip planning and navigation. When the user inputs a name or coordinates of a destination into the GPS device, or directly selects a specific location on the electronic map, the GPS device then plans a path between a detected current location and the location of the input destination, and sends voice messages to guide the user to go to the destination according to the planned path.
However, in many cases, the user probably wants to consecutively go to different destinations, though the conventional GPS device can only allow the user to adjust an existed path by means of inputting waypoints. In detail, the user has to input locations, addresses, or coordinates of the waypoints, and re-executes the path planning function, and then the GPS device can incorporate the waypoints into the trip plan, which is quite complicated. Moreover, when planning a trip, the operating interfaces of the conventional GPS device for inputting waypoints or changing the order of the waypoints are quite complicated, which may lead to great inconvenience for the user.